Tangential cutting inserts are often used with rotary milling cutters such as slotting cutters or extended-flute cutters, with turning cutting tools or the like. Examples of such use may be found in U.S. Pat. No. 3,416,209, U.S. Pat. No. 3,490,117, U.S. Pat. No. 3,701,187 and U.S. Pat. No. 4,790,693.
A conventional tangential cutting insert of the kind to which the present invention refers has a prismatic body with a clamping screw bore and with an operative front surface which is generally parallel to the clamping screw bore's axis and which is associated with upper and lower cutting edges and side edges extending therebetween and merging therewith via insert comer edges. In such conventional tangential cutting inserts, the side and comer edges are usually not used in cutting operations, being consequently not provided with appropriate cutting geometry.
WO 97/17157 discloses a double-sided indexable tangential cutting insert for face milling operations in which front and rear surfaces are each associated with upper and lower main cutting edges, two auxiliary side cutting edges therebetween and four corner edges at which the main and auxiliary cutting edges meet. The front and rear surfaces are each formed with a chip groove extending along the circumference thereof between the associated cutting edges and a planar central positioning surface projecting outwardly from the cutting edges.
It is the object of the present invention to provide a new tangential cutting insert of the above kind.